STUDY DESIGN: Case Study Series. INTRODUCTION: Restriction of forearm rotation may be required for effective management and rehabilitation of the upper limb after trauma. PURPOSE OF THE STUDY: To compare the effectiveness of four splints in restricting forearm rotation. METHODS: Muenster, Sugartong, antipronation distal radioulnar joint (DRUJ), and standard wrist splints were fabricated for five healthy participants. Active range of motion (AROM) in forearm pronation and supination was measured with a goniometer for each splint, at the initial point of sensory feedback and during exertion of maximal force. RESULTS: Repeated-measures analysis of variance indicated significant differences between splints for all four AROM measures. Post hoc paired t-tests showed that the Sugartong splint was significantly more restrictive in pronation than the Muenster splint. The antipronation DRUJ splint provided significantly greater restriction in pronation than the standard wrist splint. No splints immobilized the forearm completely. CONCLUSIONS: The Sugartong splint is recommended for maximal restriction in pronation, but individual patient characteristics require consideration in splint choice. LEVEL OF EVIDENCE: IV.